Beethoven believed his Missa Solemnis to be his best work, a labour of love and faith. Conceived on a symphonic scale, the huge demands this great and weightiest of choral masterpieces makes on his voices, treating them as instruments, are a deterrent to any but the finest choruses. Here, under the baton of Andrew Manze, the fearless and very fine BBC National Chorus of Wales – schooled by chorus director Adrian Partington – acquitted themselves admirably. They tackled the high tessitura, notably the sopranos, and the tricky fugal writing with impunity and remarkable stamina. In the context of Llandaff Cathedral, despite their slightly awkward placement in the choir stalls behind Jacob Epstein’s Majestas, they maximised the resonance and, in the parts of the mass whose prevailing mood is not at all solemn, were joyful and exultant.

Yet it was the exceptional quality of the solo quartet – treated by Beethoven as a micro-chorus, without any individual arias and set against the body of massed voices – that allowed the music’s complex structure to emerge clearly. Soprano Carolyn Sampson, mezzo Sophie Harmsen, tenor Ed Lyon and bass Darren Jeffery were particularly well-matched in terms of vivid projection and richness of tone. In music as testing as any key operatic role, they nevertheless blended together, each ceding one to the other, in the manner of a string quartet, with Sampson soaring gloriously high in crowning passages.

At the heart of the Sanctus section, the Benedictus is simply extraordinary. In it, these four voices realised a sublime expressive beauty, heightened by Beethoven’s interpolation of an ethereal solo violin, weaving in and around the vocal lines, perhaps inspired by the example of Bach and wonderfully played here by leader Lesley Hatfield. Eloquent playing by principals in the BBC National Orchestra of Wales also marked this memorable evening. There may have been the odd quibble about the occasional loss of detail in the overall wealth of sound, but this was a performance whose broadcast on Radio 3 next week should not be missed.